ADHD drug shows promise for improving cognition in Parkinson’s

Researchers from the University of Cambridge, funded by Parkinson’s UK, set out to understand more about the potential of a drug used in ADHD for Parkinson’s. Today, these results were published in the scientific journal Brain. You can read the full research results on the Oxford Academic website.

What's an ADHD drug got to do with Parkinson’s?

Atomoxetine works by boosting and rebalancing the levels of a chemical called noradrenaline in the brain. 

Noradrenaline plays a role in processing thoughts and behaviour. In Parkinson’s, an imbalance can lead to changes in thinking and processing of actions. The extent of this chemical imbalance and subsequent impact can vary from person to person. 

Previous research has shown atomoxetine could help treat impulsiveness and cognitive decline in some people with Parkinson’s. But there was no easy way to identify individuals who might benefit most from this treatment.

What’s new?

The researchers conducted a carefully controlled study in 19 people with Parkinson’s. 

Participants were given a task which involved pressing specific buttons on a keyboard. Occasionally, they would see or receive a ‘stop’ signal to stop them mid-task. The stop signals were carefully timed to assess if someone could respond to the new instruction, and how long it took. This helped the researchers see how their brains were processing thoughts and turning them into actions.

The research also involved a new type of brain scan, allowing for detailed imaging of changes in a region of the brain linked to cognitive decline. This meant researchers could see if there was a link between these changes and how someone responded to the drug. 

Atomoxetine improved participants’ ability to stop impulsive behaviour  -  to let the brain ‘stop and think’ before doing the right thing. These changes were especially profound in those with the largest changes in their brains, as identified by a scan.

The published results add further evidence that atomoxetine, which is already used in the NHS, could be quickly repurposed to become a safe and available treatment.

These promising results also show that this new type of brain imaging could play a vital role in identifying people with Parkinson's who might benefit most from this potential treatment.

Dr Claire O’Callaghan, Lead Researcher from University of Cambridge, said: 

"There has been so much progress treating the motor symptoms of Parkinson’s, but we have not seen the same gains in treating some of the hidden symptoms of Parkinson’s, like cognitive decline and impulsiveness. We know that this can be a challenging problem for people with Parkinson’s, and their families. 
 
"This is an exciting step towards individualised therapy for cognitive decline in Parkinson’s as we are now able to identify who this treatment might be suitable for. The next steps will be to carry out a clinical trial with people taking the drug for longer, and to see if it helps cognition on an everyday basis."

Dr Katherine Fletcher, Research Communications Manager at Parkinson’s UK, said: 

"Motor symptoms are largely caused by a reduction in levels of the vital brain chemical dopamine and most of the current medication works to boost or mimic the levels of this chemical within the brain. But dopamine is not the only brain chemical altered in Parkinson’s and by looking at others, researchers can potentially unlock other treatments to manage or treat different symptoms of the condition, such as cognition.

"People with Parkinson’s have identified this area as being a top priority for research because current treatments are simply not good enough. 

"By looking at what other chemicals are affected, such as noradrenaline, we are taking a step closer to finding better treatments for Parkinson’s."